Current methods for counting converted can ends in a stick of can ends employ mechanical counters using a notched wheel which rides on top of the converted can ends. The mechanical counter must exert a uniform tension on the can ends at all times to work properly. "Spong-y-ness" is a common problem among systems using such mechanical counters and is caused by slippage of the mechanical wheel with a resultant decrease in accuracy of the system. Currently, systems using mechanical counters can achieve an accuracy of only plus or minus three can ends per 480 can ends included in each output stick. Consequently, to avoid shorting customers, extra converted can ends are included in each output stick with a resultant cost increase to the manufacturer.
Systems using various methods to separate a continuous input supply of nested articles are well known. For example, U.S. Pat. No. 3,661,075 to Amberg discloses an apparatus and method for printing a design on any surface of revolution with a straight line generatrix such as cups or other cylindrical containers. The cups enter the apparatus in a nested stack and a radially extending lip on the surface of each cup is engaged by grooves cut into the periphery of two counter rotating cylinders. The grooves are formed in such a way as to cant the outer surface of the cups at an angle parallel to a rotatable print cylinder allowing a design to be printed on the cups. The rotatable print cylinder also functions as a third cylindrical support surface for the cups as they pass from the entrance end to the exit end of the device. The system and method of U.S. Pat. No. 3,661,075 uses counter rotating screws to separate and advance a nested stack of cups past a rotatable print cylinder but does not disclose any means for counting, restacking and separating sticks of objects into sticks of a known number.
U.S. Pat. No. 2,433,736 to Carew describes an apparatus for removing and delivering a cup from a nested stack into an operative position to receive fluid or semi-fluid contents. The device uses a plurality of circularly arranged cup delivery worms used to separate each cup from the nested stack of cups, hold the cup with projections comprising a cup holding station until the cup is needed, and immediately release the cup from the cup holding station permitting it to drop to a drink supply mechanism for filling with a liquid or semi-liquid. Like the Amberg patent described above, the Carew patent does not include means to count the cups as they pass through the device, or any means to restack and to separate the restacked objects into sticks of a known number.
Other methods for separating articles from a nested input stack are also employed and well known. U.S. Pat. No. 4,545,714 to Johnson et. al., for example, discloses an apparatus and method for receiving a continuous supply of nested containers and separating the nested containers into stacks having a requisite number of cups included therein. Johnson uses a rotating wheel with outwardly extending resilient members having diverging side arm portions attached thereto. The rotating wheel causes the diverging side arm portions to engage a rim portion present on each of the cups and transmit each of the cups toward the exit end of the device. At the same time, an endless conveyor chain rotates at a slightly faster speed than the rotating wheel and engages the rim portion of a container with an outwardly projecting clip at a pre-determined interval. Through suitable synchronization between the rotational speed of the rotating wheel and linear speed of the endless conveyor chain, a stack of containers having a predetermined count can be attained. U.S. Pat. No. 4,545,714 does not use rotating screws to separate the nested articles or a sensing device to count the articles.
Sensing devices used to accurately count articles are well known in the manufacturing industry. For example, U.S. Pat. No. 3,774,649 to Ward describes a system for counting and separating corrugated boxes into squared bundles. Ward uses a belt conveyor to convey flat corrugated boxes past an electric eye and into a hopper. As each flat box is conveyed past the electric eye, the count of boxes included in the bundle is increased by one. The boxes are fed into the bottom of the hopper, one by one, and when a predetermined number of boxes is attained, a stop bar is positioned to separate the current bundle from the next bundle. Boxes continue to enter the hopper and when a second electric eye positioned above the bundle senses a predetermined height of boxes, the first bundle is removed from the hopper and conveyed from the system.
None of these systems provides means for separating long sticks of converted can ends into sticks having a known number of can ends by separating, counting and restacking the can ends into stacks of exact count and do not provide an exact count of can ends to be shipped to a customer.